If you are a firm that offers support or you have a webshop, then it would be nice to have a good live-chat

www.tawk.tohas a real good app for that. It is totally free and of course you can buy some extra features - but this is not neccessary.

The free basic offers the possibility for you to have your own little logo.

With the app, your customers can mail ( if you are not online ) and if online, you can chat and you can even upload things like screenshots while you are chatting.

Users can mail the chat if wanted.

You have a dashboard and when online you can answer a chat. You can have the dashboard on your desktop, your tablet or your mobile. This way your customers can get in contact with you 24/7 - if you want that.